Migrating birds starting to reach warmer temps

The California Least Tern has foraged in the lagoon, but for the past 12 years they haven’t been spotted nesting there. Photo by Chris Mayne

ENCINITAS — It isn’t necessarily the spotting of a rare bird migrating to the area that captures the attentions and excitement of Doug Gibson, the executive director and principal scientist with the San Elijo Nature Center.

It’s more about the healthy populations of the common bird species that land at the lagoons, and especially at the San Elijo Lagoon that gets him.

“We’ve had over 300 species of birds sighted in the lagoon, and that represents about 45 percent of all bird species known in the U.S.,” Gibson said.

As the temperatures have dropped up north with the onset of winter, birds have begun their annual migration treks. Gibson and members of the nature center have already started to see the birds starting to arrive.

It’s a good thing, too, as the center readies to host their Wings over Wetlands bird spotting event Jan. 25 and Jan. 26.

For the birds that have already arrived in the area, they’ve been greeted with temperatures almost 15 degrees above the average highs.

But Gibson doesn’t think that the warmer weather has accelerated birds’ migrations.

“Migration happens from species that are moving out of colder weather… down,” Gibson said. “Once they’re here, they’re either passer-throughs, meaning they’ve stopped at their McDonald’s, which is our lagoons (and) get something to eat on the way down to where their breeding grounds are or they’re down here, this is where they come – and the weather is why we’re here.”

Though Gibson said studies from the Audubon Society have shown that a lot of migratory birds are stopping short — meaning that because of climate change and temperatures, species aren’t completing existing routes, essentially stopping short of routes by hundreds of miles, sometimes more.

For the birds flying down, the lagoon systems represent the last refuges for estuarine species and the Pacific Flyway species that are on their way to further nesting areas.

“It’s critical as a food supply for those species,” Gibson said.

“The more we’ve pinched the lagoon systems, the more we see less and less birds. And development has had an impact because there’s just less occupied area.”

The center does do monthly bird monitoring so that after several years of collecting data, and for more than 30 years, they’ve been collecting data sets. Some of that data has shown an increase and decrease in bird populations as work has been done towards maintaining the inlet.

“When we started opening the inlet, and keeping it open and transitioning the system back to a healthy estuary system, we saw a drop in water fowl, and somewhat of an increase in shorebird populations,” Gibson said.

That was to be expected, he added, because there was less standing water and more exposed mud flat habitat.

But the diversity of the bird species today still remains what they’ve had all along.

“It’s always a great time to come out and see the lagoon and having our event is a great way to become a little bit more knowledgeable on the species that are migrating here,” Gibson said.

Many of the bird species that migrate to the area can be seen, along with information about the birds, on the center’s website at sanelijo.org/animal-guide.

What they’d really like to see is the California Least Tern nesting in the lagoon. They’ve seen the small birds foraging at the lagoon, but because of predators and raccoons becoming especially good at hunting them, they haven’t nested in the area for the past 12 years.